Synthetic gas (also referred to herein as syngas), is a gaseous mixture containing hydrogen (H2) and carbon monoxide (CO), which can further comprise other gas components such as one or more of carbon dioxide (CO2), water (H2O), methane (CH4), nitrogen (N2). In the past decades, numerous processes have been developed to produce syngas due to its successful use as synthetic fuel and also in a number of chemical processes, such as synthesis of methanol, ammonia, Fischer-Tropsch type synthesis and other olefin syntheses, hydroformylation reactions, carbonylation reactions, reduction of iron oxides in steel production, etc.
Natural gas and (light) hydrocarbons are the predominant starting material for making syngas. For example, syngas can be produced using methane as the dominate feedstock, by steam reforming, partial oxidation, CO2 reforming, or by a so-called auto-thermal reforming reaction. One of the disadvantages associated with syngas production by steam reforming of methane, which is the most widely applied process to produce syngas, is that the composition of the produced gas mixture is limited by the reaction stoichiometry to H2/CO ratios of 3 or higher.
In order to avoid such drawbacks and to help counteract increasing carbon dioxide (CO2) concentrations in the atmosphere, research has been conducted to manufacture syngas from CO2 as a raw material. The conversion is based on an equilibrium reaction, reaction 1:CO+H2O⇄CO2+H2  (1)The forward reaction is known as the water gas shift (WGS) reaction, while the reverse reaction is known as the reverse water gas shift (RWGS) reaction.
There remains a need in the art for improved processes for the conversion of CO2 to syngas.